← Back to dex - Centaur: adrift between the giants +20
- Darker than charcoal +10
- Kuiper-belt object +5
- Catalogue designation only +0
Total score 35
15 more points to reach Epic.
Badges
- ❄️ Kuiper-belt object · +5
- 🔢 Catalogue designation only
- 🦌 Centaur: adrift between the giants · +20
- 🕶️ Darker than charcoal · +10
✨ Trivia
What it actually is
- 🛸 Its orbit family. A centaur, wandering between the orbits of Jupiter and Neptune on a path nothing can stabilise. Half asteroid and half comet, and gone from this orbit within a few million years.
- 🌞 Closest approach. At its nearest it comes within 5.43 AU of the Sun — inside the orbit of Saturn.
- 🔁 One lap. A single orbit around the Sun takes it about 36.3 years.
- 🥏 How far it roams. Its orbit swings between 5.43 and 16.49 AU from the Sun.
Sense of scale
- 🧱 Sense of scale. In everyday terms it is roughly 2.7× the height of Mount Everest.
- 🚶 Walk around it. Walking its equator at a steady pace, eight hours a day, would take about 1.9 days.
By the numbers
- 📐 Size. Roughly 24 km across.
What's in a name
- 🔢 Designation. Known only by its catalogue designation — no name yet.
Properties
- albedo
- 0.044
- aphelion au
- 16.48
- designation
- 2008 HY21
- diameter km
- 24
- eccentricity
- 0.5047
- full name
- (2008 HY21)
- h mag
- 12.2
- inclination
- 11.98
- mean motion deg day
- 0.0272
- moid au
- 4.42
- name
- 2008 HY21
- number only
- yes
- orbit class
- CEN
- perihelion au
- 5.426
- semi major au
- 10.96
About 2008 HY21
2008 HY21 is a rare kbo. It swings within 5.426 AU of the Sun at perihelion.
A centaur, wandering between the orbits of Jupiter and Neptune on a path nothing can stabilise. Half asteroid and half comet, and gone from this orbit within a few million years.
How to see it
Like any astronomical target, 2008 HY21 is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. Because it moves against the background stars, the live position panel on this page tracks where it is right now. The visibility panel above works out tonight's viewing window for your saved location.
Why 2008 HY21 is a rare kbo
2008 HY21 scores 35 points on Spacedle's rarity scale, which places it in the rare tier. Another 15 points would lift it into a rarer tier.
That score comes from 4 science badges — Kuiper-belt object, Catalogue designation only, Centaur: adrift between the giants and Darker than charcoal — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.